• 论文与研究报告 •

### 日本落叶松人工林枯落物土壤酶活性

1. 中国林业科学研究院林业研究所 国家林业局林木培育重点实验室 北京 100091
• 收稿日期:2014-05-02 修回日期:2015-02-05 出版日期:2015-04-25 发布日期:2015-05-20
• 通讯作者: 张守攻
• 基金资助:

国家自然科学基金重点项目"落叶松人工林长期生产力形成与维护机制的研究"(31430017)。

### Soil Enzyme Activities of the Litter in Larix kaempferi Plantation

Niu Xiaoyun, Sun Xiaomei, Chen Dongsheng, Zhang Shougong

1. Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration Research Institute of Forestry, CAF Beijing 100091
• Received:2014-05-02 Revised:2015-02-05 Online:2015-04-25 Published:2015-05-20

【目的】 深入了解不同发育阶段日本落叶松人工林不同分解程度枯落物的土壤酶活性,为促进枯落物分解、加速养分循环、缓解地力衰退提供理论依据。【方法】 以不同发育阶段日本落叶松人工林不同分解程度的地表枯落物为研究对象,在2013年5月中旬、8月初及10月中旬分别取样,测定与枯落物分解相关的8种土壤酶的活性变化及其与pH值、含水量的相关性。【结果】 除漆酶外,不同发育阶段林分枯落物层土壤酶活性基本呈现未分解层 > 半分解层 > 全分解层;不同层中起主要作用的土壤酶不同,在未分解层中主要为淀粉酶和酸性磷酸酶,半分解层中主要为漆酶和内切纤维素酶,而全分解层中主要为漆酶、内切纤维素酶和β-葡萄糖苷酶,表明淀粉酶、酸性磷酸酶在分解初期发挥主要作用,漆酶与纤维素分解酶在分解的中、后期发挥主要作用;幼龄林阶段与成熟林阶段枯落物土壤酶活性总体表现较高,近熟林较低; 在幼龄林阶段内切纤维素酶和β-葡萄糖苷酶、淀粉酶、转化酶和几丁质酶活性都较高; 成熟林阶段2种磷酸酶活性与几丁质酶活性最高,淀粉酶、转化酶与β-葡萄糖苷酶活性也较高; 近熟林阶段淀粉酶、转化酶、酸性磷酸酶、内切纤维素酶和β-葡萄糖苷酶以及几丁质酶活性都较低; 而中龄林阶段淀粉酶、内切纤维素酶和β-葡萄糖苷酶活性比幼龄林阶段酶活性低,但高于近熟林阶段酶活性;不同发育阶段林分枯落物层酶活性的变化趋势与林下植被发育状况一致,而与枯落物的贮积量变化趋势相反;对土壤酶活性的季节动态分析表明,大多数的酶在5月份活性最高,而不是温度较高的8月份;对土壤酶活性与含水量、pH值的相关性分析表明,在不同分解程度的枯落物中,半分解层土壤酶活性受含水量、pH值影响较大, 在不同发育阶段林分中,近熟林、成熟林阶段枯落物层酶活性更易受含水量、pH值影响, 在季节动态中,8月份土壤酶活性更易受含水量、pH值的影响。【结论】 不同发育阶段林分及不同分解程度的枯落物层起主要作用的酶不同;林下植被在日本落叶松人工林枯落物分解中起着重要作用,在营林中应通过间伐、疏伐来促进林下植被发育,或引入适合的林下植物;近熟林阶段日本落叶松人工林林分郁闭度大,对近熟热林阶段日本落叶松人工林进行土壤肥力管理时,应采取密度调控等切实可行的措施缓解地力衰退。

Abstract:

【Objective The aim of this study is to deepen the understanding of variation of soil enzyme activity in the litter decomposed at different extents in Larix kaempferi plantation stands at different development stages, in order to provide a theoretic basis for promoting litter decomposition, speeding up nutrient cycling and alleviating soil degradation.【Method】 Litter samples at different extents of decomposition were collected respectively in mid May, early August and mid October in 2013. Eight soil enzymes related to litter decomposition were chosen to detect their activities and relations with pH-value and water content. 【Result】 The soil enzyme activity was in the following order: un-decomposed litter layer > semi-decomposed layer > decomposed layer, except the enzyme laccase. The enzymes playing major roles were different among litter layers. The activities of amylase and acid phosphatase were the most significant in the un-decomposed litter layer. whereas the activities of laccase and endoglueanase were the highest in the semi-decomposed layer.As in decomposed layer, the activities of laccase, endo-cellulase and β-glucosidase were the most detectable. It showed that amylase and acid phosphatase played the major role in the initial decomposition stage, and laccase and cellulose played the major role in the middle and late stages. On the whole, the soil enzyme activities in the litters were higher in young and mature stands and lower in the pre-mature stand. In the young stand, the cellulase, amylase, invertase and chinase displayed higher activities. In the mature stand, the phosphatase and chinase showed the highest activity. And amylase, invertase and β-glucosidase also showed higher activities. In the pre-mature stand, the amylase, invertase, acid phosphatase, cellulase and chinase displayed lower activities. The activities of amylase, endo-cellulase and β-glucosidase were lower in the middle-age stand than in the young stand, and higher than in the pre-mature stand. The variation trends of soil enzyme activity were consistent with the growth of understory vegetation and contrary to the storage volume of litter. Most enzymes showed the highest activities in May, rather than in August in which the temperature was higher. Furthermore, the analysis of correlation of soil enzyme activity with pH-value and water content showed that soil enzyme activity were influenced by the water content and the pH-value more easily in semi-decomposed layer than in the layers with other extents of decomposition, more easily in pre-mature and mature stands than in stands at other development stages, and in August than in other months. 【Conclusion】 The soil enzymes playing the main role were different among stand development stages and among extents of litter decomposition. Understory vegetation played an important role in the litter decomposition of L. kaempfer plantation. The development of understory vegetation can be promoted by thinning or by introducing natural understory vegetation with high nitrogen content, more tolerance to shading and acid. The pre-mature stand is a turning point in the development of L. kaempfer plantation, whose canopy density is higher and understory vegetation is underdeveloped, therefore, we should pay more attention to the scientific management of pre-mature stand by implementing feasible and workable measures for relieving the soil degradation of L. kaempfer plantation.